The present invention relates to a vane compressor.
Japanese Unexamined Patent Application Publication No. H02-185692 discloses a vane compressor including a housing having a rear side plate as a partition that separates a rotor chamber from a discharge chamber. The rear side plate has on the side thereof facing the rotor chamber a first surface and on the opposite side thereof a second surface. The rear side plate has therethrough a shaft hole through which a rotary shaft is rotatably inserted. The rear side plate further has an oil passage that provides communication between the discharge chamber and the shaft hole. A cover is fixed to the rear side plate so as to face the second surface in the discharge chamber.
According to the vane compressor of the Publication, with the rotation of the rotor in the rotor chamber, refrigerant gas in the suction chamber is taken into the compression chamber and compressed. At this time, part of the lubricant oil contained in the refrigerant gas in the discharge chamber is supplied to the shaft hole through the oil passage.
A vane compressor is required to be as small as possible for improving the mountability thereof on a vehicle or the like. In the above vane compressor, it may be contemplated to reduce the dimension of the partition such as the rear side plate in the axial direction.
In this case, however, the partition tends to be bent toward the compression chamber by the pressure difference between the high-pressure discharge chamber and the compression chamber. Therefore, the thrust clearance that is provided in the axial direction between the first surface of the partition and the rotor may be reduced during the operation of the vane compressor, with the result that the resistance during the rotation of the rotor under a high load increases and a significant power loss is caused. Such problem may be significant especially when an oil passage is formed in the partition. On the other hand, if the thrust clearance is formed relatively larger, refrigerant gas in the compression chamber tends to leak out easily under a low load. Therefore, there is a fear of a drop in the volumetric efficiency of the vane compressor.
The present invention which has been made in view of the circumstances above is directed to providing a vane compressor that is small in the axial dimension and suppresses a drop in the volumetric efficiency.